Millennial disturbance‐driven forest stand dynamics in the Eastern Canadian taiga reconstructed from subfossil logs

Gennaretti, Fabio; Arseneault, Dominique; Bégin, Yves

doi:10.1111/1365-2745.12315

Cited by 15 publications

(16 citation statements)

References 47 publications

(97 reference statements)

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“…It is bordered by open spruce-moss with lichen woodlands growing on well-drained podzolic soil and regular slope. The last severe wildfire occurred at about AD 1590 along the southern section of the studied shore segment and more than 1200 years ago along the northern section (Gennaretti et al, 2014c).…”

Section: Study Areamentioning

confidence: 98%

“…We extracted α-cellulose sub-samples according to a standard protocol modified for small samples at the Delta-lab of the Geological Survey of Canada (Green, 1963;Savard et al, 2012). The extracted α-cellulose was dried at 55 • C for 12 h and sub-samples analyzed using peripherals on-line with gassource isotope ratio mass spectrometers (IRMS).…”

Section: Laboratory Treatmentmentioning

confidence: 99%

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A millennial summer temperature reconstruction for northeastern Canada using oxygen isotopes in subfossil trees

et al. 2015

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Climatic reconstructions for northeastern Canada are scarce such that this area is under-represented in global temperature reconstructions. To fill this lack of knowledge and identify the most important processes influencing climate variability, this study presents the first summer temperature reconstruction for eastern Canada based on a millennial oxygen isotopic series (δ18O) from tree rings. For this purpose, we selected 230 well-preserved subfossil stems from the bottom of a boreal lake and five living trees on the lakeshore. The sampling method permitted an annually resolved δ18O series with a replication of five trees per year. The June to August maximal temperature of the last millennium has been reconstructed using the statistical relation between Climatic Research Unit (CRU TS3.1) and δ18O data. The resulting millennial series is marked by the well-defined Medieval Climate Anomaly (MCA; AD 1000–1250), the Little Ice Age (AD 1450–1880) and the modern period (AD 1950–2010), and an overall average cooling trend of −0.6 °C millennium−1. These climatic periods and climatic low-frequency trends are in agreement with the only reconstruction available for northeastern Canada and others from nearby regions (Arctic, Baffin Bay) as well as some remote regions like the Canadian Rockies or Fennoscandia. Our temperature reconstruction indicates that the Medieval Climate Anomaly was characterized by a temperature range similar to the one of the modern period in the study region. However, the temperature increase during the last 3 decades is one of the fastest warming observed over the last millennium (+1.9 °C between 1970–2000). An additional key finding of this research is that the coldest episodes mainly coincide with low solar activities and the extremely cold period of the early 19th century has occurred when a solar minimum was in phase with successive intense volcanic eruptions. Our study provides a new perspective unraveling key mechanisms that controlled the past climate shifts in northeastern Canada

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Section: Study Areamentioning

confidence: 98%

Section: Laboratory Treatmentmentioning

confidence: 99%

A millennial summer temperature reconstruction for northeastern Canada using oxygen isotopes in subfossil trees

et al. 2015

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“…Disturbance histories are also recognized as key to understanding vegetation patterns worldwide (Johns 1986, Clark 1996, Chiarucci et al 2010, Gennaretti et al 2014). Furthermore, theory shows that disturbance can determine whether or not species coexist in ecological communities or are eliminated.…”

Section: Implications For Distribution Ecologymentioning

confidence: 99%

Disturbance and distributions: avoiding exclusion in a warming world

Sheil¹

2016

E&S

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ABSTRACT. I highlight how disturbance determines species distributions and the implications for conservation practice. In particular, I describe opportunities to mitigate some of the threats to species resulting from climate change. Ecological theory shows that disturbance processes can often slow or prevent the exclusion of species by competitors and that different disturbance regimes result in different realized niches. There is much evidence of disturbance influencing where species occur. For example, disturbance can lower the high elevation treeline, thus expanding the area for high elevation vegetation that cannot otherwise persist under tree cover. The role of disturbance in influencing interspecific competition and resulting species persistence and distributions appears unjustly neglected. I identify various implications, including opportunities to achieve in situ conservation by expanding plant species ranges and reducing species vulnerability to competitive exclusion. Suitable frequencies, scales, intensities, spatial configurations, and timings of the right forms of disturbance can improve the persistence of targeted species in a wide range of contexts. Such options could reduce the extinctions likely to be associated with climate change. More generally, these mechanisms and the resulting realizable niche also offer novel insights to understanding and manipulating species distributions.

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“…Lakes are extremely abundant and cover up to about 25% of the landscape. Numerous black spruce trees in the lakeshore forests thus become LSTs once fallen in water and eventually buried in lake sediments (Arseneault et al, 2013;Gennaretti et al, 2014aGennaretti et al, , 2014b. Black spruce LSTs https://doi.org/10.5194/bg-2020-102 Preprint.…”

Section: Study Sites and Staining Issuementioning

confidence: 99%

Chemical de-staining and the delta correction for blue intensity measurements of stained lake subfossil trees

Wang¹,

Arseneault²,

Boucher³

et al. 2020

Preprint

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Abstract. The stain of wood samples from lake subfossil trees (LSTs) is challenging the wide application of the blue intensity (BI) technique for millennial dendroclimatic reconstructions. In this study, we used seven chemical de-staining reagents to treat samples of subfossil black spruce (Picea mariana (Mill.) B.S.P.)) trees from two lakes in the eastern Canadian boreal forest. We subsequently compared latewood BI (LBI) and delta BI (DBI) time series along with conventional maximum latewood density (MXD) measured from the stained and de-stained samples. Results show that the stain of our samples is most likely caused by post-sampling oxidation of dissolved ferrous iron in lake sediments that penetrated into wood. Three reagents (ascorbic acid, sodium ascorbate and sodium dithionite all mixed with ethylenediaminetetraacetic acid) could remove > 90 % of Fe. However, even for the best chemical protocol, a discrepancy of about +2 °C compared to MXD data remains in the LBI-based temperature reconstruction due to incomplete de-staining. On the contrary, the simple mathematical delta correction, DBI is unaffected by Fe stain and shows very similar results compared to MXD data (r > 0.82) from annual to centennial timescales over the past ~ 360 years. This study underlines the difficulty of completely de-staining lake subfossil samples, while confirming the robustness of the DBI approach. DBI data measured from stained LSTs can be used to perform robust millennial temperature reconstructions.

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Millennial disturbance‐driven forest stand dynamics in the Eastern Canadian taiga reconstructed from subfossil logs

Cited by 15 publications

References 47 publications

A millennial summer temperature reconstruction for northeastern Canada using oxygen isotopes in subfossil trees

A millennial summer temperature reconstruction for northeastern Canada using oxygen isotopes in subfossil trees

Disturbance and distributions: avoiding exclusion in a warming world

Chemical de-staining and the delta correction for blue intensity measurements of stained lake subfossil trees

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